Chain line

[Reden]

When the chain is on largest sprocket it makes a almost grinding type noise. The offset from chainring seems too far. when back pedal the chain drops to lower sprocket. Spacer at BB is correct. One 2.5mm for 72mm BB.

Cranks are Race Face Turbine Cinch with standard 32t ring. 142mm rear hub. Does this on both wheel sets with different brans hubs. Mavic and Ripide.

I can only adjust the front ring inwards by 2mm as that is the only spacer left on the chain guide.

Cranks are already symmetrical around frame. By eye it seems chain line is too much towards the outside of cassette.

 

What Am I missing here?

[Falco]

Check the limit adjuster screws on the rear derailleur, it's maybe not allowing the chain to fully engage.

[droo]

B tension screw.

 

Almost guaranteed.

 

Check, when you're in the granny gear, that the top derailleur pulley isn't catching on the sprocket. If it is, adjust B screw till it's not.

[ALLMTB]

I don't think the B-tension screw has any effect on the the chain dropping when back pedaling. 

I have the exact same issue and Iv'e seen this on many 1x setups. 

@Reden, remove the chain guide and then remove the spacer between the BB and the frame on the drive side. Then check if this makes any difference. 

[Reden]

Forgot to mention it is a 1x11 setup.

 

The chain rubs against the top outside of 42t sprocket. When back pedal the chain drops from the top.

Derailer side is fine.

[popcorn_skollie]

When the chain is on largest sprocket it makes a almost grinding type noise. The offset from chainring seems too far. when back pedal the chain drops to lower sprocket. Spacer at BB is correct. One 2.5mm for 72mm BB.

Cranks are Race Face Turbine Cinch with standard 32t ring. 142mm rear hub. Does this on both wheel sets with different brans hubs. Mavic and Ripide.

I can only adjust the front ring inwards by 2mm as that is the only spacer left on the chain guide.

Cranks are already symmetrical around frame. By eye it seems chain line is too much towards the outside of cassette.

 

What Am I missing here?

 

Same boat. Make shift 1x9 restoration project.

Sram 9 speed cluster. Sram X0 9 speed RD. Sram x9 shifter.

Shimano alvin/simon/theodore crank or what ever.

Shinmano Zee chainring (non nw)

 

Chainline is bang on in 8'th sprocket.

Highs and lows set but still cannot shift to granny gear.

 

B tension screw.

 

Almost guaranteed.

 

Check, when you're in the granny gear, that the top derailleur pulley isn't catching on the sprocket. If it is, adjust B screw till it's not.

 

Ah yes. This solved the problem of getting it to shift to granny gear. Myles mentioned the same thing and it worked. But after it worked I had a new problem. Gears 1-8 now work as apposed to gears 2-9 previously. Shifting is fine up and down the rest of the cassette though. New cable and some decent shape housing I dug out.

 

And just in case it occurs to you.

Its not my jump bike and the bent rd that's on it. 

 

 

I don't think the B-tension screw has any effect on the the chain dropping when back pedaling. 

 

I didn't think that either but adjusting the b screw did get me back my granny. As for back pedaling mine drops in gears 1-3/4. Back pedaling on the rest of the cluster is fine.

 

I'm pretty sure chain line is my problem. Luckily I'm still using a crank that comes with a spider. Unfortunately the Zee ring has clearance issues when trying to bolt it behind the spider with this crappy Shimano Atlantis or what ever crank.

Edited September 27, 2017 by popcorn_skollie

[droo]

I don't think the B-tension screw has any effect on the the chain dropping when back pedaling. 

I have the exact same issue and Iv'e seen this on many 1x setups. 

@Reden, remove the chain guide and then remove the spacer between the BB and the frame on the drive side. Then check if this makes any difference. 

 

On a 1x setup nothing will stop the chain dropping to a lower gear when backpedalling. The only thing that'll do this is not backpedalling.

 

The B screw will stop the pulley from grinding on the granny gear though. And make the shifting a whole lot better.

[droo]

Oh, and Skollie - probably either a pap spring or the cage is catching on the cable routing magafter. If #2, the chain is a link too long.

[Bigjim]

I align my chainline around gear 3-4 & have no issues. You need to play around with BB spacers & chainring spacers

[FrikkieMeyer87]

To have the best possible chance of this not occurring when I did my 1x11 conversion, I ordered some chainring spacers from Rapide to get the chainring as close as possible to the granny gear. That being said, a friend who helped me with the conversion fiddled with the deraileur screws till the top- and bottom limits and pulley distance from the cassette in the granny gear. After that, I found that I had to run the shifter cable rather pap in order to get to all the gears without scratching, but now it's running lekker. Perhaps also check your cable tension. Adjust it back and forth with the barrel screw on the shifter and see what difference it makes. Worth a try, no tools required